Schematic diagrams include multiple components to illustrate the subject matter of the particular diagram. The subject matter of the schematic drawings may be varied and may include hydraulics, HVAC, electrical and/or any other type system. The schematic drawings described herein may be electrical wiring diagrams for illustration, but not limitation. For example, in the aircraft industry, electrical wiring diagrams are used to illustrate all of the conductive paths among the various elements of the aircraft. Thus, the term component used herein refers to any type of element included in the particular schematic diagram to illustrate the desired subject matter. In electrical wiring diagrams, for instance, components include modules, line replaceable units, plugs, switches, buses, power sources, grounds, wires, connectors, etc.
Typically, the schematic diagrams are embodied in set of multiple hard copy sheets that each include a relatively small portion of the overall schematic diagram. Thus, each sheet in a set includes references to other sheets where the portion of the schematic diagram is continued. These references are typically called “off-sheet references.” The hard copy sheet sets are very time-consuming and difficult for users, such as maintenance personnel, to use, particularly when they need to reference more than one component, because they must manually locate one of the components in the sheets and then trace the connection to the other component through sometimes multiple sheets. In addition, many times a component is illustrated on multiple sheets, such as when the component is included in more than one conductive path. Thus, a user must first locate the sheet that includes the desired conductive path associated with the component.
Due to the difficulties involved in manually locating and tracing various components and conductive paths in schematic diagrams that are embodied in sets of multiple hard copy sheets, techniques have been developed for creating electronic schematic diagrams that are much easier and less time-consuming to utilize. For example, the electronic schematic diagrams contain automatic links among the various sheets, such that a user may easily see all of the conductive paths associated with a particular element and may easily navigate through the schematic. Examples of the technologies that create the electronic schematic diagrams and the associated features of the electronic diagrams are discussed in detail in U.S. Pat. No. 6,606,731, entitled “Intelligent Wiring Diagram System,” U.S. patent application Ser. No. 09/971,283, entitled “Method, Computer Program Product, and System for Performing Automated Linking Between Sheets of a Drawing Set,” U.S. patent application Ser. No. 09/971,155, entitled “Method, Computer Program Product, and System for Creating and Viewing an Intelligent Graphics File Including Parts Information,” and U.S. patent application Ser. No. 09/971,149, entitled, “Method, Computer Program Product, and System for Performing Automated Text Recognition and Text Search Within a Graphic File.” The contents of each of these applications are hereby incorporated by reference in their entirety.
In many electronic schematic diagrams, it is desirable to illustrate the direction of flow through at least a portion of the components. In the example of an electronic wiring diagram, if the user is going to work on a particular component, the user may wish to know the direction of current flow though the component, such as which direction from the component the power source is located and which direction from the component the ground is located. Thus, if a user is going to work on a blown fuse or circuit breaker, the user must determine the direction from which the fuse or circuit breaker is powered. To determine the direction of flow, the user must manually trace through the elements that connect to the component at issue to determine which direction from the component the ground is located and/or which direction the power source is located. Because current flows from the source to the ground, the user knows the direction of flow through the component once the user determines which side of the component is connected to the power source and/or which side of the component is connected to the ground. Although the example of electronic wiring diagrams is used above, this situation also applies to other types of diagrams, such as hydraulics diagrams to determine the direction of fluid flow through a component, such as a valve. Thus, in any type of diagram the direction of flow may be determined by locating the flow source and/or the flow termination relative to the component(s) at issue.
Manually tracing through the elements that connect to a component typically involves accessing multiple pages of a drawing set illustrating the components of a system. The user must then study the drawings to determine how the various sheets of the drawings relate to one another. Once the user find the component at issue in the drawings, then the user must trace the elements that connect to the component through the multiple pages of the drawing set until the user finds the flow source, such as the power source, and/or flow termination, such as a ground.
Typically, the multiple pages of the drawing set are in hard copy form, such as in manuals, such that the user must physically sift through the pages of the drawings to trace the elements. Alternatively, the multiple pages of the drawing set may be electronically represented, such that the user must repeatedly “pan” and “zoom” to trace the elements through the pages. Each of these techniques is tedious, time-consuming, error-prone and can require a great deal of expertise. As such, there is a need for a technique that is capable of automatically and efficiently discovering and presenting the flow through one or more components represented in a drawing set.